I play 3 classes equally, Uh dk, afflic lock, and priest (shadow) since mop. Have played disc in wotlk loved the offensive play but that has diminished. New blood fear change looks promising "Talents
Blood Fear While active, any time an enemy melee attack deals damage to the caster they will become afflicted by Fear. for up to until cancelled. Blood Fear Lasts 60 sec." So I might make my lock my caster priest my healer and uh dk my melee. As you can see I like dot/pet classes lol. MW looks like fun though, rolling around the map, port like a lock, offensive abilities for fistweaving is getting buffed i believe. Maybe its worth leveling one in the downtime before patch?

Mistweaver should be much funnier than pala, but anyway it will always be subjective. MW has huge potential burst healing, probably the highest in game ( at high mana cost thou), the down side is cc vulnerability. You need to be good in playing out of los, kiting, and this kind of things. Your mobility makes damage dealers crying. Fistweaving is not so important in PvP, because of mentioned before cc vulnerability. MW is best in RBGs, then 5s, and finaly 3s are really demanding.

I play mistweaver in arenas with hunter (2s), and with hunter and rogue (3s). It's maybe not a very long experience yet, but looks promising.